Why do your ribs hurt when you run?

Ribs hurt while running because when a person runs, his breathing accelerates and results in over straining of intercostal muscles. This causes ache. There acn be an active or healed fracture of rib/s which might be causing friction. Lung conditions like emphysema also cause pain after running.

The reason why your ribs hurt when you run is because of a pain called a stitch. The reason for the stitch is actually unknown. Some researchers call it a physiological response while others say that it is a lack of oxygen to the diaphragm. The stitch is actually quite harmless but the pain is real enough.

You have muscles in your ribcage that you only use when you are breathing heavily, such as when running. Since these muscles do not normally get used when you breathe, they cramp and hurt when you do start using them.